渭河流域1850—2005年降水及蒸发量变化时空特征

为了探究渭河流域过去气候变化规律及其影响因素,基于CMIP5模式输出产品,采用双曲线插值方法获取渭河流域56个站点1850—2005年降水、蒸发及气温数据。采用最小二乘法、M-K突变检验、小波分析及ArcGIS空间插值方法分析了渭河流域气候要素的多尺度时空特征。结果表明:渭河流域近156 a来年均气温、降水为上升趋势,趋势率分别为0.028℃/10 a,0.09 mm/10 a,年蒸发量为减少趋势,趋势速率为-5.1mm/10 a,温度和降水季节变化与年变化基本趋于一致,蒸发量的减少主要发生在夏秋两季。渭河流域中游、下游与南部降水相对变率变化趋势基本一致,而上游与泾河及洛河支流降水相对变率趋势一致,相对变率在-2.8%～14.98%。整个流域温度、蒸发量相对变率为-2.3%～-3.47%及-2.35%～6.54%。各气候要素均存在5～20 a的短周期变化以及110 a长周期变化,气温及蒸发分别在1986年及1963年发生突变现象,降水无突变点出现。总体而言,渭河流域近156 a气候呈现暖湿化趋向,降水及蒸发存在明显的空间分异以及周期性规律。

Temporal and Spatial Characteristics of Precipitation and Evaporation in the Weihe River Basin from 1850 to 2005

In order to explore past climate change law and its influencing factors in the Weihe River Basin, based on the output products of the CMIP5 model, the hyperbolic interpolation method was used to obtain the precipitation, evaporation and temperature data of 56 stations in the Weihe River Basin from 1850 to 2005. Multi-scale temporal and spatial characteristics of climate elements in the Weihe River Basin were analysed by the least square method, M-K mutation test, wavelet analysis and ArcGIS spatial interpolation method. The results show that the average annual temperature and precipitation in the Weihe River Basin have been increasing for the past 156 years, with trend rates of 0.028℃/10 a and 0.09 mm/10 a, respectively. The annual evaporation is on a decreasing trend, with a trend rate of -5.1 mm/10 a, the seasonal changes of temperature and precipitation are basically consistent with the annual changes, and the decrease in evaporation mainly occurs in summer and autumn. In the middle reaches of the Weihe River basin, the trend of relative precipitation variability in the lower reaches is basically the same as that in the south, while the trend of relative precipitation variability in the upper reaches is the same as that of the Jinghe and Luohe tributaries. The relative variability is between -2.8% and 14.98%. The relative change rate of the temperature and evaporation in the entire basin is -2.3%～-3.47% and -2.35%～6.54%. All climatic elements have short-period changes of 5～20 a and long-period changes of 110 a. The temperature and evaporation had abrupt changes in 1963 and 1986, respectively, and there is no abrupt change in precipitation. In general, the climate of the Weihe River Basin has shown a trend of warming and humidification in the past 156 years, and there are obvious spatial differences and periodic regularities in precipitation and evaporation.